Olefin polymers such as polyethylene, polypropylene, ethylene/α-olefin copolymers, and propylene/α-olefin copolymers are produced by (co)polymerizing olefins in the presence of an olefin polymerization catalyst such as a metallocene-based solid catalyst composed of a solid catalyst containing a metallocene compound of a group 4 metal such as zirconium and an organoaluminum component, for example.
However, in some cases, slurry polymerization of olefins in the presence of such a metallocene-based solid catalyst produces polymer masses and causes sheeting of polymers in the polymerization vessel and causes polymers to adhere to the impeller or vessel wall, thereby failing to achieve long-term stable operation. Gas-phase polymerization of olefins in the presence of such a metallocene-based solid catalyst in a fluidized bed reactor in some cases produces polymer masses and causes sheeting of polymers in the fluidized bed and decreases the flowability of polymer particles, thereby causing an inhomogeneous polymerization state in the fluidized bed and failing to achieve stable long-term continuous operation.
Chemical systems such as petroleum distillation refinery plants and polyolefin manufacturing plants suffer from problems of a decreased heat exchange capability and pipe clogging caused by fouling. This may lead to instability of manufacturing operation and, in worst cases, plant shutdown. Avoiding such situation is thus highly desirable.
In order to address these problems, for example, Patent Literature 1 (Hereinafter “Patent Literature” is referred to PTL, such as PTL 1) discloses a method in which a higher aliphatic amide is added to a powder flowing environment field for polyolefin production. However, according to this method, the activity of the polymerization catalyst used in polyolefin production decreases and the catalyst cost increases. PTL 2 discloses polymerization process that uses a catalyst constituted by a solid catalyst prepared by olefin prepolymerization and a surfactant supported on the solid catalyst. According to PTL 3, polymerization is conducted by feeding a surfactant during polymerization in the presence of a solid catalyst prepared by prepolymerization of olefins. However, although these techniques offer some effects of preventing adhesion of polymers to the impeller and vessel wall, the polymerization activity significantly decreases. An effective polymerization method that can achieve high activity while reducing the fouling on the vessel wall and the impeller has not yet been found.